About a month ago a warning signal on the dash board of my 2002 2.2 Hdi auto estate C5 indicated "anti pollution fault" among others including ABS failure The car contined to drive satisfactorily and after a while the alarms ceased only to return at a later date with a loss of power, driving below 50mph was satisfactory. The car has been into the main Citroen garage in Leicester five time and faults such as loose connection, blown fuse, faulty pressure sensor have been diagnosed. On each occasion the fault has reoccurred within a day or so of picking up the car. The car has been service regularly and up to now has been trouble free. What is the solution please?